We call a crash a run-off-road crash if the roadside played a significant role in crash circumstances or outcome. Run-off-road crashes can be single-vehicle crashes that occur on the roadside and do not involve other road users, but also multiple-vehicle crashes in which a vehicle slips onto the roadside after a crash with another vehicle and collides with an obstacle. Crashes in which a vehicle goes off the road, then back onto the road colliding with another road user can also be described as roadway departure crashes, of which run-off-road crashes are a subgroup.
Most run-off-road crashes are single-vehicle crashes. Run-off-road crashes typically end when a vehicle hits an obstacle, overturns or hits the water. In this fact sheet, the focus is on run-off-road crashes. Other types of roadway departure crashes are not considered.